Reinforcement of natural rubber (NR) using nanofillers often results in an enhancement of the tensile strength, but at the expense of elongation at break and toughness. In this study, with the objective of strengthening NR without compromising its compliance, we investigate the reinforcement efficiency of a series of cellulose nanofibers (CNF) with variations in residual hemicellulose, lignin and therefore surface chemistry. Different types of high aspect ratio CNF isolated from Triodia pungens (T. pungens), an Australian arid grass commonly known as spinifex, were added at 0.1-2 wt% loadings into a pre-vulcanized NR latex. CNF/NR nanocomposites then were benchmarked against NR nanocomposites incorporating a well-known wood-derived CNF. It was found that the presence of residual lignin and hemicellulose, and the pretreatment with a deep eutectic solvent, a mixture of choline chloride and urea (CCU), could increase the compatibility of CNF with the NR matrix, while still enabling stability and handling of the colloidal latex mixture. Incorporation of 0.5 and 0.1 wt% of the sodium hydroxide treated CNF and choline chloride/urea treated CNF into the NR latex showed respectively 11 and 17% enhancement in tensile stress, and importantly without compromising viscoelastic properties; while addition of 0.1 wt% wood-derived CNF resulted in 18% decrease in both tensile stress and strain coupled with more pronounced latex stiffening.
Luminescent solar concentrators (LSCs) have recently gained popularity as an effective solution to increase solar energy conversion. Utilizing LSCs together with solar cells can generate more energy at a lower cost than using only solar cells. LSCs operate by utilizing luminophores, molecules that absorb incident solar irradiation and re‐emit photons, and waveguides that redirect emitted photons to the edges of a glass or polymer slab at high concentrations. Many quantum dots (QDs) have been the focus of much research as luminophores for LSCs, owing to their high quantum yields (QYs), controllable absorption/emission spectra, good stability, and ease of synthesis. Various QDs, such as CdSe, PbS, CdS, AgInS2, Si, and C, have been modified to enhance their optical performances in LSCs, often measured by their optical efficiencies, internal/external quantum efficiencies, and power conversion efficiencies. This review appraises the latest developments in colloidal QDs—basic QDs, doped QDs, core/shell QDs, hybrid QDs, and Si‐based QD—for their applications in LSCs. Other factors that enhance an LSC's efficiency, such as altering the polymer matrix and using distributed Bragg reflectors, are discussed. The development of highly efficient, QD‐based LSCs will be essential for increasing solar energy production worldwide.
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